Tags

Introduction

The Ignition tag systems provides data points that can be static values, expressions, sql queries, or come from OPC. Tags support a great number of features, such as alarming, scaling, and historical storage.

Tags are stored in tag providers. By default, a fresh Ignition installation will have an internal tag provider - this can be thought of as a standard internal tag database. Additionally, it is possible create external DB-based tag providers (SQLTagsTM), thus turning your SQL database into the tag database. This ability opens up some very flexible architectures, where multiple systems share tags through the database.

Main benefits of the Ignition Tag System

Tags work naturally in Ignition to offer many exciting features:

Drag and Drop screen design

Using the Vision module, drag and drop tags onto a window to automatically create new bound components. Drag tags onto existing components or properties to quickly bind them to the data. Creating powerful status and control screens is literally just clicks away!

Object-Oriented Design

Use Tag UDTs (user-defined data types)  to design re-usable, parameterized, and extendable data types. New instance tags can be created and configured in seconds, potentially saving a tremendous amount of time over traditional tag systems.

Performance and Scalability

Tags offer terrific performance on both the gateway and client side. On the gateway side, the system can support thousands of value changes per second, and hundreds of thousands of tags overall. On the client side, the tag system a lightweight subscription model to increase efficiency. Adding additional clients creates a nearly negligible effect on the database and gateway performance.

Integrated component feedback

SQLTags feature a quality and overlay system for Vision module components. If a tag's data quality is anything but good, a component that depends on it will get a visual overlay. Input components display an animated overlay while write pending requests are being written. These features effectively communicate the status of the system at a glance.

One-click historical logging with Tag HistorianTM

Tag Historian makes it easier than ever to store and use historical data. By simply selecting a checkbox on a tag, historical data will be stored in an efficient format in your SQL database, and will be available for querying through scripting, historical bindings and reporting. Drag-and-drop tags directly onto an EasyChartTM to create trends, or onto a table to display historical values. Tag Historian's robust querying features give you great flexibility in how you retrieve the data.

Powerful Alarming Model

Each tag can have any number of alarms configured on it. There are many different alarm modes accommodating simple digital alarms, analog high/low value alarms, as well as more specialty alarms like bad data quality and bit-packed alarms. The settings for alarms may be bound to other tags, making the alarm configuration dynamic. You can attach associated data to alarms to turn the alarm journal into a forensic tool to help determine the state of your process when issues occurred.

Getting started with Tags

See the Tags section under Project Design for more information about creating and using tags and tag historian.